Bluebonnets grow best in soils that are alkaline, moderate in fertility, and most important of all, well drained. Full sun is also required for best growth. Seed may be planted September 1 through December 15; however, for best results, plant seeds no later than mid-November. This allows seed time to germinate and grow throughout the winter months, during which time a heavy root system and a sturdy plant is developed to produce an abundance of spring flowers. Seeds. Bluebonnets produce large, hard-coated seeds that may cause them to have a low germination rate the first year or two. As the hard seed coats wear down by rain, abrasion and decay, the seedlings begin to sprout. Sowing Seeds: Soil preparation is not necessary; the seed can be broadcast over undisturbed soil. However, seed to soil contact is essential. When sowing seed in turf areas, make sure to scalp the grass as low as possible with a mower and rake up any thatch which may prevent the seed from contacting the soil. Small areas can be sown by hand or with a mechanical hand device. Large areas require a seed drill or other mechanical means that can be calibrated for the seeding rate. For small areas, or places where you want a good display more quickly, seed companies recommend using 8 to 10 seeds per square foot. At that rate an ounce will cover approximately 135 square feet, and 1/2 a pound covers 1,000 square feet. An acre will require 20-30 pounds of seeds. Soil: After seeding, it is best to cover the seed with soil no more than one-quarter inch deep. This protects the seed from being eaten by birds or "baked" by the sun. Water thoroughly but gently. Fertilizer: Fertilizing is not recommended. Soil Bacterium: Be aware that one of the reasons bluebonnets fail to bloom is the lack of an essential bacterium in the soil. This nitrogen fixation is needed for the bluebonnets to bloom.